Power provider Ausgrid said it was investigating "multiple localised outages" in Sydney and on the Central Coast, with about 14,000 customers affected.

The NSW Rural Fire Service (RFS) has fire bans in place for Greater Sydney and the Hunter region.

Extra crews have been placed on standby as winds of between 40 and 45 kilometres per hour are forecast.

RFS Commissioner Shane Fitzsimmons said the total fire ban covered areas experiencing very high fire conditions.

"The total fire bans are again in force today for the Greater Sydney environment which includes the Blue Mountains and the Central Coast, but also the Greater Hunter region which is effectively from Newcastle up through the Hunter to places like Scone and Muswellbrook," he said.

In other incidents, two men aged 33 and 48 remain in hospital in a critical condition after being pulled from unpatrolled beaches near Wollongong — one at Bulli's Sandon Point and the other further south near Port Kembla.

CEO of Surf Life Saving NSW, Steve Peace, warned members of the public to be extremely careful on the state's beaches.

"Please, come to the beach it will be fantastic but you must look for those iconic symbols the red and yellow flags," he said.

"And you must swim where our lifeguards and lifesavers can see you."

A rock fisherman in his 20s from Western Sydney, who was not wearing a life jacket, died after falling into the water at Currarong in the Shoalhaven region on Sunday morning.